About the Warsaw method
The Warsaw method is a mealtime insulin-dosing approach for people with type 1 diabetes who use an insulin pump. It grew out of research at the Medical University of Warsaw showing that meals high in fat and protein produce a slower, more prolonged rise in blood glucose than carbohydrate alone - often spread over 3 to 8 hours after eating. The method converts the fat and protein in a meal into fat-protein units (FPU) so that an extended (square) or dual-wave bolus can be sized and timed to cover that delayed rise, on top of the normal bolus for carbohydrate.
How the calculation works
Fat contributes about 9 kcal per gram and protein about 4 kcal per gram. Adding those calories together and dividing by 100 gives the number of fat-protein units in the meal, since 1 FPU is defined as 100 kcal from fat and protein. The same total calories are then treated as roughly one-tenth as glycemic as carbohydrate, which converts them into a carbohydrate-equivalent in grams. Dividing that carbohydrate equivalent by your insulin-to-carb ratio gives the extra insulin needed for the fat and protein, on top of whatever is dosed for the meal's actual carbohydrate.
Extended bolus duration
Pump training materials built around the Warsaw method commonly use a step table to set how long the extended portion of the bolus should run: roughly 3 hours for up to 1 FPU, 4 hours for up to 2 FPU, 5 hours for up to 3 FPU, and up to 8 hours for larger fat-protein loads. Many pumps deliver this as a dual-wave bolus, combining an immediate dose with the fat/protein portion spread evenly across that window; the exact split and duration should be set with a diabetes care team and refined using real glucose data.
When to consult a professional
This calculator performs the standard Warsaw method arithmetic - it does not replace individualized dosing advice. Insulin-to-carb ratios, correction factors, and extended-bolus timing should be set and adjusted by your endocrinologist or diabetes educator based on your own glucose patterns, and any change to your dosing should be discussed with your care team first.